An ad hoc network is a self-configuring network of mobile nodes connected by wireless links—the union of which form an arbitrary topology. The nodes are free to move randomly and organize themselves arbitrarily; thus, the network's wireless topology may change rapidly and unpredictably. Ad hoc networks comprise mobile nodes that communicate via multihop wireless channels, which are usually deployed in unattended environments. The ability to construct and operate an ad hoc network without the need of any wired infrastructure (e.g., base stations, routers, and the like) makes ad hoc networks a promising candidate for military, disaster relief, and law enforcement applications.
There has been a rapidly growing interest in the use of directional antennas in ad hoc networks. Such antennas have the ability to concentrate radiated power towards the intended direction of transmission or reception, thereby reducing the amount of radiated power necessary to reach a node. As a result, the energy efficiency of ad hoc network protocols may be greatly improved. For example, in military applications, directional networking provides important capabilities that may afford the warfighter better communications facilities in specific operational scenarios. These capabilities may include improved data rates, reduced observability, greater spectral reuse, and better immunity to intentional and unintentional interference. Directional networking has emerged as a key technology for realizing the next generation Anti-Jam (AJ), low probability of intercept/low probability of detection (LPI/LPD), and bandwidth efficient communication systems suitable for ad hoc network applications. Directional networking may be critical to enabling network-centric applications for the Future Combat System (FCS) and Warfighter Information Network—Tactical (WIN-T).
To realize an efficient ad hoc directional communication system that is able to provide the aforementioned benefits, the conventional approach is based on directional protocols that point steerable directional antennas such as phased array antennas (PAA) and the like. This conventional approach has been the focus of most near-term efforts including, for example, FCS and Networked Data Link (NDL).
Using the conventional approach, however, directional networks are frequently limited in size and often require additional information on node locations due to the difficulty of locating and tracking network nodes through a narrow aperture.
Thus, it would be desirable to provide an ad hoc large scale directional network, in which a node may receive data from one or more nodes without a priori knowledge of the transmitter direction.